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Causes, Risk Factors, and Prevention
Risk Factors
A risk factor is anything that affects your chance of getting a disease such as cancer.
Learn more about the risk factors for acute myeloid leukemia.
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What Are the Risk Factors for Acute Myeloid Leukemia?
Do We Know What Causes Acute Myeloid Leukemia?
Prevention
There is no way to completely prevent cancer. But there are things you can do that
might lower your risk. Learn more.
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Can Acute Myeloid Leukemia Be Prevented?
What Are the Risk Factors for Acute
Myeloid Leukemia?
A risk factor is something that affects your chance of getting a disease, such as cancer.
Different cancers have different risk factors. Some risk factors, like smoking, can be
changed. Others, like a person’s age or family history, can’t be changed.
But having a risk factor, or even several risk factors, does not mean that you definitely
will get the disease. And many people who get the disease may have few or no known
risk factors. Even if a person has a risk factor and develops cancer, it’s often very hard
to know how much that risk factor contributed to the cancer.
There are some known risk factors for acute myeloid leukemia (AML).
Smoking
The only proven lifestyle-related risk factor for AML is smoking. Many people know that
smoking is linked to cancers of the lungs, mouth, throat, and larynx (voice box), but few
realize that it can also affect cells that don’t come into direct contact with smoke.
Cancer-causing substances in tobacco smoke are absorbed by the lungs and spread
through the bloodstream to many parts of the body.
Certain chemical exposures
The risk of AML is increased by exposure to certain chemicals.
For example, long-term exposure to high levels of benzene is a risk factor for AML.
Benzene is a solvent used in the rubber industry, oil refineries, chemical plants, shoe
manufacturing, and gasoline-related industries, and is also found in cigarette smoke,
gasoline and motor vehicle exhaust, and some glues, cleaning products, detergents, art
supplies, and paints.
Some studies have linked heavy workplace exposure to formaldehyde with AML risk,
but this link has not been seen in some other studies.
Certain chemotherapy drugs
Patients with cancer who are treated with certain chemotherapy (chemo) drugs are
more likely to develop AML.
Drugs called alkylating agents and platinum agents are linked to an increased risk of
AML that peaks about 8 years after chemo. Often a patient will get a disease called
myelodysplastic syndrome before the AML. Examples of alkylating agents include
cyclophosphamide, mechlorethamine, procarbazine, chlorambucil, melphalan, busulfan,
and carmustine. Platinum drugs include cisplatin and carboplatin.
Chemo drugs known as topoisomerase II inhibitors are also linked to AML. AML linked
to these drugs tends to occur only a few years after treatment and without
myelodysplastic syndrome developing first. Examples of topoisomerase II inhibitors
include etoposide, teniposide, mitoxantrone, epirubicin, and doxorubicin.
For more information, see Second Cancers in Adults.
Radiation exposure
High-dose radiation exposure (such as being a survivor of an atomic bomb blast or
nuclear reactor accident) increases the risk of developing AML. Japanese atomic bomb
survivors had a greatly increased risk of developing acute leukemia, most often about 6
to 8 years after exposure.
Radiation treatment for cancer has also been linked to an increased risk of AML. The
risk varies based on the amount of radiation given and what area is treated, but is not
as high as was seen after the atomic bomb blasts.
The possible risks of leukemia from exposure to lower levels of radiation, such as from
imaging tests like x-rays or CT scans, are not well-defined. If a fetus is exposed to
radiation within the first months of development, it may carry an increased risk of
leukemia, but the extent of the risk is not clear. If there is an increased risk it is likely to
be small, but to be safe, most doctors try to limit radiation exposure from tests as much
as possible, especially in children and pregnant women.
For more information, see X-rays, Gamma Rays and Cancer Risk.
Certain blood disorders
People with certain blood disorders seem to be at increased risk for getting AML. These
include chronic myeloproliferative disorders such as polycythemia vera, essential
thrombocythemia, and idiopathic myelofibrosis. The risk of AML is increased further if
treatment for these disorders includes some types of chemotherapy or radiation.
Some people who have myelodysplastic syndrome (MDS) may develop AML. Patients
with MDS have low blood cell counts and abnormal cells in the blood and bone marrow.
MDS can evolve over time into AML. Patients who develop AML after having MDS
typically have a poor prognosis.
Genetic syndromes
Some syndromes that are caused by genetic mutations (abnormal changes) present at
birth seem to raise the risk of AML. These include:
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Fanconi anemia
Bloom syndrome
Ataxia-telangiectasia
Diamond-Blackfan anemia
Schwachman-Diamond syndrome
Li-Fraumeni syndrome
Neurofibromatosis type 1
Severe congenital neutropenia (also called Kostmann syndrome)
Some chromosome problems present at birth are also linked to a higher risk of AML,
including:
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Down syndrome (being born with an extra copy of chromosome 21)
Trisomy 8 (being born with an extra copy of chromosome 8)
Family history
Although most cases of AML are not thought to have a strong genetic link, having a
close relative (such as a parent or sibling) with AML increases your risk of getting the
disease.
Someone who has an identical twin who got AML before they were a year old has a
very high risk of also getting AML.
Older age
AML can occur at any age, but it becomes more common as people get older.
Male gender
AML is more common in males than in females. The reason for this is not clear.
Uncertain, unproven or controversial risk factors
Other factors that have been studied for a possible link to AML include:
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Exposure to electromagnetic fields (such as living near power lines)
Workplace exposure to diesel, gasoline, and certain other chemicals and solvents
Exposure to herbicides or pesticides
So far, none of these factors has been linked conclusively to AML. Research in these
areas is ongoing.
References
See all references for Acute Myeloid Leukemia
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Last Medical Review: December 9, 2014 Last Revised: February 22, 2016
American Cancer Society medical information is copyrighted material. For reprint
requests, please contact [email protected].
Do We Know What Causes Acute
Myeloid Leukemia?
Some people with acute myeloid leukemia (AML) have one or more known risk factors
(see “ What are the risk factors for acute myeloid leukemia?”), but many do not. Even
when a person has one or more risk factors, there is no way to tell if it actually caused
the cancer.
Scientists have learned how certain changes in DNA can cause normal bone marrow
cells to become leukemia cells. Normal human cells grow and function based on the
information contained in each cell’s chromosomes. Chromosomes are long strands of
DNA in each cell. The DNA inside our cells makes up our genes – the instructions for
how our cells function. We tend to look like our parents because they are the source of
our DNA. But our genes affect more than how we look.
Some genes control when our cells grow, divide to make new cells, and die at the right
time. Certain genes that help cells grow, divide, or live longer are called oncogenes.
Others that slow down cell division or make cells die at the right time are called tumor
suppressor genes.
Each time a cell prepares to divide into 2 new cells, it must make a new copy of the
DNA in its chromosomes. This process is not perfect, and errors can occur that affect
genes within the DNA. Cancers can be caused by DNA mutations (changes) that turn
on oncogenes or turn off tumor suppressor genes. For instance, changes in certain
genes such as FLT3, c-KIT, and RAS are common in AML cells. These types of
changes can help cells grow out of control.
Mutations in specific genes are found in many cases of AML, but larger changes in one
or more chromosomes are also common. Even though these changes involve larger
pieces of DNA, their effects are still likely to be due to changes in just one or a few
genes that are on that part of the chromosome. Several types of chromosome changes
may be found in AML cells:
Translocations are the most common type of DNA change that can lead to
leukemia. A translocation means that a part of one chromosome breaks off and
becomes attached to a different chromosome. The point at which the break occurs
can affect nearby genes – for example, it can turn on oncogenes or turn off genes
like RUNX1and RARa, which would normally help blood cells to mature.
Deletions occur when part of a chromosome is lost. This can result in the cell losing
a gene that helped keep its growth in check (a tumor suppressor gene).
Inversions occur when part of a chromosome gets turned around, so it’s now in
reverse order. This can result in the loss of a gene (or genes) because the cell can
no longer read its instructions (much like trying to read a book backwards).
Addition or duplication means that there is an extra chromosome or part of a
chromosome. This can lead to too many copies of certain genes within the cell. This
can be a problem if one or more of these genes are oncogenes.
Different cases of AML can have different chromosome changes, and some changes
are more common than others. Doctors are trying to figure out why these changes occur
and how each of them might lead to leukemia. For example, some are more common in
leukemia that occurs after chemotherapy for another cancer.
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Some changes seem to have more of an effect on a person’s prognosis (outlook) than
others. For instance, they may affect how quickly the leukemia cells grow, or how likely
they are to respond to treatment. This is discussed in more detail in “ How is acute
myeloid leukemia classified?”
Some people with certain types of cancer have inherited DNA mutations from a parent
that increase their risk for the disease. Although this can happen in some cases of AML,
such as in the genetic syndromes discussed in the “ What are the risk factors for acute
myeloid leukemia?”, inherited mutations are not often a cause in AML.
Most DNA changes related to AML occur during a person’s lifetime, rather than having
been inherited before birth. Some of these acquired changes may have outside causes
like radiation or cancer-causing chemicals, but in most cases the reason they occur is
not known. They seem to happen more often as we age, which might help explain why
AML usually occurs in older people.
References
See all references for Acute Myeloid Leukemia
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Last Medical Review: December 9, 2014 Last Revised: February 22, 2016
American Cancer Society medical information is copyrighted material. For reprint
requests, please contact [email protected].
Can Acute Myeloid Leukemia Be
Prevented?
It’s not clear what causes most cases of acute myeloid leukemia (AML). Since most
people with AML don’t have risk factors that can be changed, at the present time there
is no known way to prevent most cases of AML.
Smoking is by far the most significant controllable risk factor for AML, and quitting offers
the greatest chance to reduce a person’s risk of AML. Of course, non-smokers are also
much less likely than smokers to develop many other cancers, as well as heart disease,
stroke, and some other diseases.
Treating some other cancers with chemotherapy and radiation may cause secondary
(post-treatment) leukemias. Doctors are trying to figure out how to treat these cancers
without raising the risk of secondary leukemia. But for now, the obvious benefits of
treating life-threatening cancers with chemotherapy and radiation must be balanced
against the small chance of getting leukemia years later.
Avoiding known cancer-causing chemicals, such as benzene, can lower the risk of
getting AML. But most experts agree that exposure to workplace and environmental
chemicals seems to account for only a small portion of leukemia cases.
References
See all references for Acute Myeloid Leukemia
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Last Medical Review: December 9, 2014 Last Revised: February 22, 2016
American Cancer Society medical information is copyrighted material. For reprint
requests, please contact [email protected].
2016 Copyright American Cancer Society